Rivers and Lakes (1:24000 and 1:100000) Metadata

The Lakes and River features are based upon the National Hydrography Dataset (NHD). The NHD includes all hydrographic features (streams, rivers, and water bodies including lakes, wetlands, estuaries and coastlines) depicted on the US Geological Survey's (USGS) 1:24000 and 1:100000 scale topographic maps.

The NHD is the culmination of cooperative efforts of the USGS, U.S. Environmental Protection Agency (USEPA) and various state and local partners. It combines elements of USGS digital line graph (DLG), hydrography files, and the USEPA Reach File (RF3). The NHD supersedes RF3 and DLG files by incorporating them, not by replacing them.

For more information on the NHD, visit http://nhd.usgs.gov.

Some characteristics of the National Hydrography Dataset:

It is a feature-based dataset that interconnects and uniquely identifies the stream segments or "reaches" that make up the Nation's surface water drainage system.

Unique reach codes (originally developed by the USEPA) are provided for networked features and isolated water bodies.

The reach code structure is designed to accommodate higher resolution data. Common identifiers uniquely identify every occurrence of a feature.

It is currently based on the content of the USGS 1:100,000-scale data, giving it accuracy consistent with those data.

Names with GNIS identification numbers are included for lakes, other water bodies, and many stream courses.

NHD provides flow direction and centerline representations through surface water bodies.

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